Melt the butter in a large stock pot. Add flour, salt and pepper, and stir until combined. Add milk and chicken broth, using a whisk to incorporate. Cook over medium heat, whisking often until thick and bubbly.

When potatoes are cool enough to handle, use a spoon to scoop out the insides into the stock pot. Use a long-handled spoon to smash the potatoes into bite-sized pieces. Crumble the bacon into the pot. Heat thoroughly, stirring often.